The present invention relates to a gasification reactor comprising a gasifier with a tubular gastight wall arranged within a pressure vessel.
Gasification reactors can for instance be used for the production of synthetic gas by partial combustion of a carbonaceous feed, such as pulverized coal, oil, biomass, gas or any other type of carbonaceous feed.
Some gasification reactor types comprise a gasifier only having a discharge opening at its lower end for discharging syngas via a discharge—generally referred to as dip tube—into the slag collection bath. Due to the pressure build-up in the gasifier freshly produced synthetic gas containing slag and fly ash particles is forced to flow down through the dip tube and the slag collection bath around the lower edge of the dip tube to be recollected in the annular space between the dip tube and the pressure vessel wall. The water in the slag collection bath cleans and cools the synthetic gas.
During operation of the reactor, slag is continuously deposited on the inside of the gastight wall of the gasifier. Slag slides down from the inner surface of the gasifier wall and drops via the discharge opening into the slag collection bath. If the slag slides slowly the discharge opening in the gasifier is reduced by accumulation of slag lumps, which can eventually lead to blockage of the opening. This causes a build up of overpressure in the gasifier, which can cause substantial damage.
In other cases, an overpressure may develop in the annular space between the gasifier wall and the pressure vessel, for instance caused by a defect in the supply of water to the slag collection bath or by defective valves in the reactor's supply or discharge infrastructure.